Who said it?

I have found a quote I've been looking for. It's the lower one in my signature right now: "Science is everything we understand well enough to explain to a computer. Art is everything else."

However I don't know just who said it. Most web sources say David Knuth, but some say Donald Knuth. Of the two, Donald is a lot more famous, but I don't know if the quote is attributed to him by a minority of sources because Donald is famous, David said it, and some people were confused, or if the majority of sources unthinkingly quoted one original source that said David and it was really Donald who said it. There is a David Knuth who works in technology, according to Google. Anyone know who said this quote?